Modeling MOFs for Environmental Cleanup and Beyond

Posted: October 2019

Tina Nenoff’s favorite technology right now are the supercomputers at Sandia National Laboratories that are allowing her to model metal-organic frameworks (MOFs) like never before. New modeling tools are enabling more rapid synthesis and testing that are moving MOFs increasingly out of the lab and into society.

Nenoff’s team at Sandia is working to develop MOFs that detect specific gases in the environment after accidental release and in separating specific gases from the air. She is known for her work on MOFs in cleaning up after nuclear accidents. “I find it very exciting to work with industry in moving our basic and applied research through the ‘valley of death’ to commercialization and implementation,” Nenoff says.

Material Insights spoke with Nenoff about her research, how she got started in MOFs, and future directions she sees for the field.

The opinions expressed herein do not represent an endorsement of NuMat.

Insights: How did you first become interested in MOFs? Do you remember your first encounter with them?

Nenoff: I was educated and trained as a zeolite chemist and crystallographer in the lab of Professor Galen Stucky at UCSB. It was while there in the very early ‘90s that I first learned of interesting phases that originated in New Zealand around 1990, and then shortly thereafter the beautiful work of Professor Omar Yaghi’s group in metal organic frameworks. However, I remained in zeolite and molecular sieve chemistry through the 1990s at Sandia for energy efficiency and nuclear waste cleanup applications. It was in the mid- to late 2000s that I started applying MOFs to fission gas capture for nuclear energy and accident applications.

Insights: What are you most proud of in terms of your contributions to the field?

Nenoff: I am most proud of our contribution to the world of environmental cleanup. We at Sandia were the leading edge of researchers using MOFs for fission gas cleanup (in particular, iodine gas) from nuclear accidents. We have since evolved our work toward novel direct electrical readout sensors that use MOFs to target and detect iodine gas in the environment. We envision this as a life-saving technology that will notify the public immediately after an explosion or gas release.

Insights: What excites you most about the MOF field of research at this particular moment in time?

Nenoff: I am very much excited about the opportunities in tying materials design by modeling to the synthesis, testing and model validation of MOFs. We use DFT [Density Functional Theory] and AIMD [Ab Initio Molecular Dynamics] modeling to design and predict the energetics of preferential gas molecule binding to different metal centers and organic ligands combinations in MOFs. This enables us to design a structure for targeted applications. Then we synthesize the designed MOF, test it for gas selectivity. This is a true multidisciplinary method of making new materials.

We at Sandia have successfully applied this method to the design and discovery of a MOF that shows high selectivity for oxygen from air at ambient conditions. There are a few companies using our material for scale-up and complex gas testing. We are excited to see them succeed.

Insights: How have you seen the field evolve over the last 5-10 years?

Nenoff: I think the field has been very focused on two areas: (1) MOFs targeted to gas adsorption areas for limits set by the Department of Energy, for example hydrogen storage; and (2) beautifully designed novel MOFs with higher and higher surface areas. More recently, I’ve seen MOF science and engineering branching out into new more specialized target areas in an effort to increase commercialization uses, such as chemical warfare destruction, drug delivery, and caustic gas adsorption.

Insights: How do you see your research evolving in the future?

Nenoff: The historical focus of my work has been generally for the nuclear energy industry. Future research will be more directed toward the chemical/petrochemical industries; with very fundamental research into the chemistries and mechanisms of acid gas destruction or adsorption into tuned and designed MOFs. Leveraging that research for optical gas sensors is ongoing, too.

Insights: What do you think needs to happen to make MOFs more ubiquitous in society? What might this look like in 10 or 20 years?

Nenoff: The biggest challenges for MOFs include commercialization and getting broad-scale adoption into society. Use of technoeconomic analysis to show cost-effective implementation into industrial processes is necessary for acceptance of MOFs. In 10-20 years, I see that creative implementation of MOFs into society will help bring costs down, and therefore become more accepted in key industries (chemical/petrochemical) as viable commodity chemicals.

Insights: What do you see as the biggest misconceptions about the field from industry?

Nenoff: The biggest misconceptions are that these materials are too delicate for industrial processes and too expensive. MOFs are new to the market in comparison to metal oxides or zeolites/molecular sieves and therefore still need to be accepted as materials whose cost will scale with production and implementation.

Insights: I know you have been highlighted in an NSF-sponsored book about women in engineering. What is it like to be a woman in this field?

Nenoff: As a woman, I feel very accepted by the field, probably because it is multidisciplinary and has participants from many fields such as materials science, chemical engineering, organic chemistry, inorganic chemistry, and computational modeling. My team at Sandia is overwhelmingly female, but we strive to include as many men into our team as possible, too.

 


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